1. Field of the Invention
This invention relates to an apparatus and a method for processing an image which allows an improvement in the resolution of an edge portion and fine lines of the image while enabling the reproducibility of gradation of a non-edge portion of the image to be maintained.
2. Description of Related Art
Various techniques for enabling the image of an original document read out by such an image reading device as the scanner to be reproduced as faithfully as permissible in the form of a printed image have been heretofore proposed.
One of these techniques which is disclosed in JP-A-09-191,402, for example, comprises preparing two matrixes different in resolving power and identical in size and selecting either of the matrixes which conforms the characteristic to be required of a relevant image thereby effecting the maintenance of the resolving power in a region in need of the resolving power and attaining the reproducibility of gradation in a region in need of reproducibility of gradation.
When such an area gradation reproduction method as mentioned above is adopted, however, an effort to obtain the reproducibility of gradation in a wide range generally results in inevitably creating discontinuous contours between an edge portion and fine lines of the image resulting in a rugged sensation and degrading the resolution thereof. Conversely, when important consideration is given to the resolution, the problem of having to sacrifice the reproducibility of gradation arises in spite of the advantage that the edge portion and fine lines are reproduced with clearly defined contours.